1. Field of the Invention
The present invention generally relates to removable ground anchor bodies using springs. More particularly, the present invention relates to a ground anchor body having a rotation release structure configured such that a PC strand, a deformed bar or the like coupled to the anchor body can be reliably maintained in the coupled state, and when needed, the PC strand, the deformed art or the like can be easily separated and removed from the anchor body.
2. Description of the Related Art
Generally, slope reinforcement structures provided with PC strands, deformed bars or the like are formed by a method including: forming a bore in the ground; inserting a tension member having a high tensile strength with an internal fixer and an anchor body into the bore; injecting grouting material such as concrete or the like to firmly fix the tension member in place; and applying a load to a free end of the tension member and fixing the free end in place using an external fixer to prove sufficient fixing force. Such slope reinforcement structures structure to stably support structures such as retaining walls and are widely used in works for preventing loss of earth and sand from a section of soft ground or in sheathing works for preventing collapse of the peripheral ground during an excavation work for underground structures in construction or civil engineering works.
Tension members used for such slope reinforcement structures are produced by twisting several deformed bars or steel wires. Such deformed bars or tension members have high strength, but if they are left on the ground they may act as obstacles causing problems pertaining to indemnification or the like when neighboring areas are developed later.
To avoid the above-mentioned problems, an internal fixer for removable ground anchors was proposed. This internal fixer is configured such that deformed bars or tension members that have been embedded in the ground can be easily removed after the construction has been completed.
Such a conventional anchor body includes: a cylindrical body with an inclined surface formed in the cylindrical body; a wedge that is disposed on the inclined surface of the body and divided into about three parts, with a tension member disposed in a central space among the three parts; and an elastic spring provided on a rear end of the wedge to elastically compress the wedge forward and prevent the tension member from being undesirably displaced or removed.
In the structure of this conventional anchor body, when needed, the tension member can be removed, after the tension member is compressed and the wedge disposed in the cylindrical body is moved backward while the central space among the parts of the wedge is expanded. However, even after the wedge is moved backward, the central space of the wedge may not be reliably expanded. Although the wedge is moved backward and the central space of the wedge is expanded, the spring continuously compresses the rear end of the wedge, thus making it difficult to remove the tension member from the anchor body, whereby the tension member may be reliably separated from the anchor body.
Furthermore, in the case of the conventional removable internal fixer, if a shock is applied to the internal fixer for PC strands when transporting a PC strand produced from a factory to a construction site or conducting a construction work, the tension member may not be easily removed later.
Moreover, if the anchor body that has been in the coupled state is undesirably separated by an external shock, it is almost impossible to reassemble the anchor body in a construction site, thus disrupting the progress of the construction.
In an effort to overcome the above problems, another conventional technique was introduced in Korean Patent Registration No. 10-0963565, filed by the applicant of the present invention.